Obesity myths

Today, professors Campos and Brownell combat misinformation about America's problem with weight. Yesterday, they discussed the best public policies for reducing obesity; Tuesday, it was the government's rationale for intervening on the issue, and on Monday they attempted to define the parameters of the problem. Tomorrow, they'll end with a discussion about the cultural components of the debate.

So much nonsense, so little timeBy Paul F. CamposKelly,

So much nonsense surrounds the subject of weight, food and health that it's difficult to choose just a few items from the buffet of myths and misconceptions served up to us on a daily basis. Here are some selections from the menu:

Americans are getting fat because they're eating more. In fact, as Steven Blair points out, "we do not have data on average daily energy expenditure or on changes in this variable, and the data we have on average daily energy intake are questionable. Therefore the fundamental cause of the increases in obesity prevalence observed over the past several years cannot be determined."

Calorie-dense foods and drinks, especially in schools, are making American kids fat. Again, almost all studies of these issues have failed to find any significant correlation -- let alone a causal relationship -- between the consumption of "junk" food and higher weight in children (there may be good reasons for banning soda drinks and the like from schools, but doing so to stem a supposed "obesity epidemic" among children is not one of them).

We've become a nation of couch potatoes. At the risk of repetition, we simply don't know if Americans are now less active than they have been historically -- the data just aren't available.

Losing weight is merely a matter of regulating calories in versus calories out. In turns out the human body is a vastly more complex mechanism than a car engine, and the simple logic behind the idea that people will lose weight by eating less and exercising more isn't simple as much as it's hopelessly simplistic.

If everyone had a healthy lifestyle, all or almost all of us would be within the weight range the government currently defines as "healthy" or "normal." This is perhaps the most pervasive and scientifically unsupported myth of all. In fact, we have every reason to believe that a very large proportion of the population cannot and indeed should not try to maintain anything like what is (falsely) defined as a "normal" weight.

All over the developed world, fully half or more of the adult population weighs more than our public health agencies say we ought to weigh. Yet increasing rates of "overweight" and "obesity," so-called, correlate closely with increasing affluence -- as does steadily increasing life expectancy and steadily improving health for people of all ages.

Are we suffering from an "obesity epidemic" -- or rather from an epidemic of wrongheaded definitions and scientifically baseless claims?

In that regard, I was particularly disappointed to see you claim that "this generation of American children is expected to be the first in the nation's history to lead shorter lives than their parents did." This sort of statement gives unwarranted respectability to a much-cited editorial in a prominent medical journal that said the same thing. Yet this editorial offered no statistical basis for its opinion -- an opinion that flies directly in the face of the available evidence.

In all candor, I expect better from you. I've always considered you one of the few prominent obesity researchers who it was possible to respect -- but this sort of claim sounds more like the alarmist rhetoric cranked out by pharmaceutical industry lobbying groups disguising themselves as supposedly disinterested organizations, rather than a sincere scientific argument.

Paul Campos is a professor of law at the University of Colorado, and syndicated columnist for Scripps Howard News Service. His most recent book is "The Obesity Myth."

One myth rises above all others. It affects public opinion about what drives America's diet, how politicians respond to increasing obesity, what we permit of the food industry, and the health of the nation.

It is captured in two words -- personal responsibility -- and relies on several assumptions: a) adverse changes in the nation's diet and exercise result from irresponsible behavior; b) there is no social or corporate responsibility; and c) people who suffer from problems such as diabetes bring it on themselves.

The myth has strong, well-funded and politically powerful proponents, most notably the food industry, its trade associations and political figures influenced by industry lobbyists. One example is the National Restaurant Assn. and its state affiliates who use their considerable political muscle to oppose actions such as offering calorie values on restaurant menus (despite more than 80% of the public favoring such action) while trumpeting the personal-responsibility mantra.

Personal responsibility is not a hard sell in a country steeped in Puritan values of hard work, discipline and self-restraint. It works in some contexts but has two fundamental flaws when considering the nation's diet -- it is wrong and it leads down a failed and unproductive path. Every country in the world has increasing rates of obesity. Are people becoming irresponsible in remote islands in the Indian Ocean, poor African countries, China, India and everywhere else? People who move to the U.S. tend to gain weight, and those who move from the U.S. tend to lose. Laboratory animals given calorie-dense foods sold in any convenience store will ignore healthy foods and as much as triple their body weight. When the environment promotes obesity, weight will rise.

Economists use the term "optimal defaults" to describe conditions that promote beneficial or healthy choices. Enrollment in pension plans, for instance, is in an employee's interest and in the interest of society (people will have retirement savings). Harvard economist David Laibson and his colleagues found that some employers enroll people as a matter of course but give employees the opportunity to opt out. Using this method, nearly 100% of employees will enroll. Other employers do not enroll automatically but offer the opportunity to opt in; about 50% of people enroll in the first year with this approach. There is an optimal default. We could reduce traffic deaths by just imploring people to wear seat belts, drive slowly and avoid dangerous roads, but we install air bags. We could deal with air and water pollution by asking citizens to be responsible (wear masks and boil water), but instead we monitor industry, have emissions standards for cars, etc.

The nation's diet is driven by terrible defaults. Large portions, a tidal wave of food marketing directed at children, schools selling unhealthy foods, and economic policy that makes healthy food cost more than calorie-dense processed foods are but a few examples of defaults that take a massive toll on the nation's health and well-being.

The challenge is to create better defaults. This will be possible only when we turn from blaming people for irresponsible actions to giving the nation what it deserves -- conditions that make responsible behavior the easy choice.